1. Field
The present invention relates to a washing machine, including a bubble generator, which is capable of removing a wash residue left in a drum and a water tub through the operation of the bubble generator, and a control method thereof.
2. Description of the Related Art
Generally, a washing machine (normally, a drum type washing machine) is an apparatus, including a water tub to store water (wash water or rinse water), a cylindrical drum rotatably installed in the water tub to receive laundry, and a motor to generate a drive force necessary to rotate the drum, to remove contaminants from the laundry by surface activities of a water current and a detergent.
The washing machine performs washing through a series of operations, such as a washing operation to separate contaminants from laundry with water containing a detergent (specifically, wash water), a rinsing operation to rinse bubbles or residual detergent from the laundry with water containing no detergent (specifically, rinse water), and a spin-drying operation to spin-dry the laundry at a high speed. When washing is performed through such a series of operations, a process to drain contaminant water from the drum and the water tub is carried out after the completion of the washing operation and the rinsing operation.
The drainage process includes a stoppage drainage to drain contaminant water from the drum and the water tub while the supply of water is stopped and a water supply drainage to drain contaminant water from the drum and the water tub while the supply of water is performed. During the drainage (the stoppage drainage or the water supply drainage), a wash residue (specifically, foreign matter such as detergent waste or nap) generated during the washing operation or the rinsing operation is discharged together with contaminated water (drainage water).
During the drainage process, most of the wash residue is discharged together with the drainage water. However, some of the wash residue is not discharged but is left in the drum or between the drum and the water tub. For example, during the stoppage drainage, only the drainage water is drained while the wash residue stays or settles, with the result that the wash residue is left in the drum and the water tub. On the other hand, during the water supply drainage, the wash residue between the drum and the water tub is discharged to some extent by supplied water, but the wash residue at the bottom of the water tub and in the drum is not easily discharged, with the result that the wash residue is left in the drum and the water tub as in the stoppage drainage. When the wash residue (specifically, detergent waste) is continuously left, bubbles are continuously generated during a subsequent rinsing operation, which brings about dissatisfaction of users with the product. Also, laundry may be contaminated again by the contamination of the drum and the water tub, which lowers rising efficiency.